Bulbs are sand-blasted with a range of patterns that project onto the wall, or onto a removable flat glass shade.
Here's some text from Zero, which basically repeats what we've just said:
Light Shadows are developed together with Orrefors Kostaboda. The tall, slender standard lamp features a removable, flat shade. When the lamp is lit, shadows are projected on the shade by the patterns sand-blasted into the bulb.
If the shade is removed, the lamp becomes more strictly graphic, like a mere emblem of a lamp. Light Shadows is sold by Orrefors. For more information: www.orrefors.com